HYPE-CFDEM

Single-screw extrusion is a key technology for manufacturing plastic items like foils, pipes, and profiles. To make single-screw extrusion more efficient, faster, and produce better quality products, researchers are studying the three main steps involved in the process, namely 1) the transport of the plastic granules from the hopper, 2) the compression of the granules between screw and barrel, and 3) the melting of the granules. Even though there are models that describe these steps individually, there is not yet a comprehensive model that covers the entire process. As a result, designing and optimizing SSE machines still requires a lot of trial and error, which is both costly and time-consuming. The goal of this project is to create a digital twin, namely a virtual model of the single-screw extruder, that can accurately simulate the transport, compression, and melting of plastic in one seamless process. This model uses a combination of two advanced simulation techniques: the Computational Fluid Dynamics (CFD) and the Discrete Element Method (DEM). The CFD simulates fluids like air and molten plastic, while DEM focuses on the individual plastic pellets. The coupled CFD-DEM model must be developed and validated to allow a proper simulation of the single-screw extrusion. The model development includes: 1) improved contact laws for the plastic pellets that considers their elasticity, plasticity, and stickiness, 2) a better representation of the flow of molten plastic and 3) a more accurate method for capturing the interface between air and molten plastic. The new model will be tested and validated using experimental data provided by the project partner. The project is a collaboration between DCS Computing GmbH and the Institut für Kunststofftechnik (IKT) from the University of Stuttgart, and it represents a continuation of the joint project 3D- MOPSE (I3202-N34).